In traditional projection technologies such as liquid crystal display (LCD), cathode ray tube (CRT), and plasma monitors, each pixel of the display is designed to emit light uniformly across the specified viewing region. Similarly, for rear projection theater-style systems, each pixel of the projector is designed to scatter light off the screen uniformly across the specified viewing region. There are many advantages to such traditional projection technologies, among them being that technological complexity is low and there is no need to know the viewer's position beyond the fact they are assumed to be in the viewing region. Also, one image is used for many viewers and there is no need for special viewing apparatuses (with exceptions like 3D glasses). Alternatives to three-dimensional (3D) projection include lenticular and holographic approaches, but only with varying degrees of success.